The present invention relates generally to automated analytical instruments and more particularly to automated analytical instruments for conducting assays for components of interest in fluid samples.
In recent years, a number of automated instruments have been developed to perform analyses of fluid samples. As is known in the art, such instruments may be used to test various types of biological fluids for substances of interest, for example, to find evidence of disease, to monitor therapeutic drug levels, and the like. Typically, such automated analytical instruments utilize either liquid reagents or dry reagents to assay for a substance of interest. Various different types of assay devices are known for use in such automated instruments including, for example, dry thin-film multilayer assay elements which are typically mounted in an assay module and capillary assay devices.
Generally speaking, automated analytical instruments for conducting assays for substances of interest in fluid samples typically include a plurality of containers for holding the fluid samples to be tested and may include containers for holding the desired reagents. The instruments also typically include one or more fluid dispensing units for metering out quantities of the fluid samples to be analyzed, a temperature controlled chamber wherein the assay devices are allowed to incubate for an appropriate period of time, an analyzing system for measuring some property related to the substance of interest in the fluid samples being tested and some mechanism for bringing the sample holding containers to a location where they can be accessed by a fluid dispensing unit.
In copending, commonly assigned United States patent application Ser. No. 08/461,169, filed Jun. 05, 1995, which is a continuation of application Ser. No. 732,053, filed Jul. 18, 1991, now abandoned, in the name of Robert C. Maclndoe, Jr. there is disclosed an automated analytical instrument of the type which uses assay modules to perform assays for components of interest in fluid samples. The instrument includes a supply apparatus for holding a supply of assay modules, a testing system which includes apparatus for testing the fluid samples using the assay modules, a fluid sample cup holder having a plurality of fluid sample holding cups, a pair of fluid sample dispensing units and an assay module transfer apparatus for transferring an assay module to be used from the supply apparatus to the testing system. The assay module transfer apparatus includes an assay module transfer unit which is mounted on a supporting structure and is movable vertically. The assay module transfer unit includes a mechanism for pulling the assay module out of the assay module supply apparatus and a mechanism for pushing the assay module so obtained into the testing system. By moving the assay module transfer unit vertically, the assay module transfer unit can be aligned with assay modules disposed at different levels in the supply apparatus. In the operation of the instrument, the fluid sample cup holder travels back and forth between fluid dispensing units wherein quantities of fluid samples are dispensed into the assay modules being used for testing the fluid samples.
In U.S. Pat. No. 4,152,390, there is described an automated chemical analytical instrument which includes, in addition to a testing system wherein the testing takes place, a supply unit for holding a plurality of assay modules and a transfer apparatus for transferring an assay module from the supply unit to the testing system. The assay modules are stacked in containers, which may be received in a nest of the analyzing apparatus with a spring biased plunger arranged to enter the container through an opening. The plunger engages a movable element located in the container behind the stack of modules to urge the top module forwardly toward the testing system portion of the instrument. The instrument also includes a sample tray which is removably mounted on a pair of tracks. A plurality of cups containing the biological fluids to be tested are placed, presumably by the operator, onto the sample tray.
As can readily be appreciated, the need exists for an automated analytical instrument for conducting assays of fluid samples which includes a more automated arrangement for transporting the containers having the fluid samples to be tested to the fluid dispensing unit (or units) and then moving the containers out of the way after quantities of the fluid samples to be tested have been withdrawn.